Ozone decomposition catalyst and method for decomposing underwater pollutants by using same

Abstract

The present invention relates to an ozone decomposition catalyst and a method for decomposing underwater pollutants by using same and, particularly, to an ozone decomposition catalyst that facilitates the conversion of ozone into hydroxyl radicals, and thus can improve the efficiency of an advanced oxidation process using ozone.

Description

Ozone decomposition catalyst and method for decomposing water pollutants using the same

[0001] This invention claims the benefit of Korean Patent Application No. 10-2024-0108068 filed with the Korean Intellectual Property Office on August 13, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an ozone decomposition catalyst and a method for decomposing pollutants in water using the same, and more particularly, to an ozone decomposition catalyst capable of improving the efficiency of an advanced oxidation process using ozone by promoting the conversion reaction of ozone into hydroxyl radicals.

[0003] Advanced oxidation processes using ozone are a technology that can non-selectively remove various trace pollutants, including organic substances, contained in water by decomposing ozone to generate hydroxyl radicals (·OH), which are powerful oxidizing substances. Ozone can decompose trace pollutants through two mechanisms. The first is direct decomposition, in which ozone directly reacts with pollutants. The second is indirect decomposition, in which hydroxyl radicals generated by the decomposition reaction of ozone react with pollutants. Direct decomposition by ozone selectively acts on only some trace pollutants, whereas indirect decomposition by hydroxyl radicals has the advantage of being able to decompose most pollutants through a non-selective reaction.

[0004] However, the reaction in which ozone decomposes and converts to hydroxyl radicals is slow and the amount converted is small. Furthermore, the reactor must be large to ensure sufficient reaction, and additional processes are required to remove unreacted residual ozone. Therefore, research has been conducted on a catalytic ozone oxidation process that additionally adds a catalyst to accelerate the ozone decomposition reaction.

[0005] Meanwhile, most of the substances known to be used as catalysts to promote ozone decomposition reactions contain transition metals or transition metal oxides, so there was a problem that the catalyst components could leak out during the water treatment process, causing secondary pollution.

[0006] The technical problem to be achieved by the present invention is to provide an ozone decomposition catalyst that improves the efficiency of decomposing pollutants in water by promoting the reaction in which ozone is converted into hydroxyl radicals, without concern for secondary pollution due to leakage of catalyst components.

[0007] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0008] One embodiment of the present invention provides an ozone decomposition catalyst comprising carbon nitride and an alkali metal ion attached to the carbon nitride.

[0009] Another embodiment of the present invention provides a method for manufacturing an ozone decomposition catalyst according to an embodiment of the present invention, comprising the steps of preparing carbon nitride; and mixing a precursor including the carbon nitride and an alkali metal and then heating them together.

[0010] Another embodiment of the present invention provides a method for decomposing pollutants in water, comprising the steps of: (a) injecting an ozone decomposition catalyst according to an embodiment of the present invention into polluted water; (b) injecting dissolved ozone into the polluted water; and (c) oxidizing and decomposing pollutants in the polluted water using hydroxyl radicals generated by the ozone decomposition catalyst decomposing the dissolved ozone.

[0011] An ozone decomposition catalyst according to one embodiment of the present invention can improve the speed of an ozone decomposition reaction in which dissolved ozone (O3) is decomposed and converted into hydroxyl radicals.

[0012] An ozone decomposition catalyst according to one embodiment of the present invention can completely decompose ozone and leave no residual ozone, and therefore, an additional process for removing residual ozone is not required in an advanced oxidation process using the catalyst.

[0013] A method for decomposing underwater pollutants according to one embodiment of the present invention can non-selectively remove various pollutants and can have a fast removal rate.

[0014] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the attached drawings.

[0015] Figure 1 is a drawing schematically showing the chemical structure of an ozone decomposition catalyst according to one embodiment of the present invention.

[0016] Figure 2 is a drawing showing an SEM image and an EDS image of an ozone decomposition catalyst of a manufacturing example.

[0017] Figure 3 is a drawing showing the XRD analysis results for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example.

[0018] Figure 4 is a drawing showing the results of FT-IR analysis for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example.

[0019] Figure 5 is a drawing showing the XPS analysis results for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example.

[0020] Figure 6 shows the ozone concentration and desethyl-atrazine concentration measured for deionized water samples collected in examples and comparative examples.

[0021] Figure 7 is a diagram showing the calculated exposure amount of hydroxyl radicals and the conversion rate of ozone into hydroxyl radicals for examples and comparative examples.

[0022] Figure 8 is a diagram showing the ESR analysis results of an experimental example.

[0023] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0024] Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0025] Throughout this specification, the unit “parts by weight” may mean the weight ratio between each component.

[0026] Throughout this specification, “A and / or B” means “A and B, or A or B.”

[0027] Hereinafter, the present invention will be described in more detail.

[0028] ozone decomposition catalyst

[0029] One embodiment of the present invention provides an ozone decomposition catalyst comprising carbon nitride and an alkali metal ion attached to the carbon nitride. The ozone decomposition catalyst according to one embodiment of the present invention serves as a catalyst for an ozone decomposition reaction in which dissolved ozone (O3) is decomposed and converted into hydroxyl radicals, thereby improving the reaction rate.

[0030] In the present invention, the alkali metal ion attached to carbon nitride means an alkali metal in an ionic state, such as carbon nitride (CN x ) can mean that it is bonded with atoms.

[0031] According to one embodiment of the present invention, the alkali metal ion attached to the carbon nitride may form a coordination bond or an ionic bond with the carbon nitride.

[0032] According to one embodiment of the present invention, the alkali metal ion is Na + and K +It may include one or more selected from among. Preferably, the alkali metal ion is Na + and K + may include.

[0033] According to one embodiment of the present invention, the carbon nitride may include graphite-phase carbon nitride (g-C3N4).

[0034] According to one embodiment of the present invention, the graphite-like carbon nitride has a layered structure of a two-dimensional planar structure, and a single layer may have a repeated structure of triazine or tris-s-triazine (heptazine) with a melamine structure as a basic unit.

[0035] According to one embodiment of the present invention, the graphite-like carbon nitride may include a defect. The defect may refer to a chemical structure that deviates from the basic lattice structure of the graphite-like carbon nitride. According to one embodiment of the present invention, the defect may be formed at the terminal portion of the chemical structure of the graphite-like carbon nitride.

[0036] According to one embodiment of the present invention, the defect formed in the graphite-like carbon nitride is a cyano group (-C≡N), O - and N - It may include one or more of the following:

[0037] Figure 1 is a schematic diagram showing the chemical structure of an ozone decomposition catalyst according to an embodiment of the present invention. Referring to Figure 1, an alkali metal ion included in an ozone decomposition catalyst according to an embodiment of the present invention forms a coordination bond with pyridinic nitrogen (Pyridinic N) atoms of graphite-like carbon nitride or an anionic group of a defective portion, N - -C≡N or O - It can be attached to carbon nitride by forming an ionic bond.

[0038] According to one embodiment of the present invention, the content of the alkali metal element included in the ozone decomposition catalyst may be 1 to 10 at%. Specifically, the content of the alkali metal element included in the ozone decomposition catalyst may be 1 to 10 at%, 3 to 10 at%, 5 to 10 at%, 1 to 7 at%, 3 to 7 at%, or 5 to 7 at%.

[0039] According to one embodiment of the present invention, the ozone decomposition catalyst may be porous. More specifically, the ozone decomposition catalyst may be formed in the form of porous particles in which two or more carbon nitride layers to which an alkali metal is attached are irregularly laminated.

[0040] According to one embodiment of the present invention, in the FT-IR analysis spectrum for the ozone decomposition catalyst, 2000 to 2400 cm -1 At least one peak may appear in the region of . More specifically, in the FT-IR analysis spectrum for the ozone decomposition catalyst, the peak may be in the region of 2150 to 2250 cm -1 At least one peak may appear in the region.

[0041] An ozone decomposition catalyst according to one embodiment of the present invention can decompose dissolved ozone to generate hydroxyl radicals. An ozone decomposition catalyst according to one embodiment of the present invention can rapidly remove pollutants in an advanced oxidation process using ozone by decomposing dissolved ozone to generate hydroxyl radicals, and can completely decompose ozone to leave no residual ozone, eliminating the need for an additional process to remove residual ozone.

[0042] According to one embodiment of the present invention, it may be possible to generate hydroxyl radicals by promoting an ozone decomposition reaction expressed by the following reaction formulas (1) to (3).

[0043] Reaction equation (1): O3+ e -→ O 3· -

[0044] Reaction formula (2): O 3· - + H + → HO3·

[0045] Reaction formula (3): HO 3· → OH·

[0046] According to one embodiment of the present invention, the ozone decomposition reaction expressed by the reaction formulas (1) to (3) can be promoted by the ozone decomposition catalyst according to the present invention regardless of whether light is irradiated.

[0047] According to one embodiment of the present invention, the ozone decomposition reaction expressed by the reaction formulas (1) to (3) can be promoted by the ozone decomposition catalyst according to the present invention regardless of whether light is irradiated.

[0048] The reaction pathway by which dissolved ozone decomposes to produce hydroxyl radicals in the absence of a catalyst can be expressed by the following reaction formula (4).

[0049] Reaction formula (4):

[0050]

[0051] Referring to the above reaction formula (4), dissolved ozone in the absence of a catalyst can react with hydroxyl ions to self-decompose and generate hydroxyl radicals through a series of reactions. The ozone decomposition reaction according to reaction formula (4) has limitations in that the overall reaction rate is slow and the amount converted to hydroxyl radicals is small.

[0052] An ozone decomposition catalyst according to one embodiment of the present invention can increase the rate of generation of hydroxyl radicals and the conversion rate of ozone into hydroxyl radicals by promoting the ozone decomposition reaction expressed by the reaction formulas (1) to (3).

[0053] Method for manufacturing ozone decomposition catalyst

[0054] Another embodiment of the present invention provides a method for producing an ozone decomposition catalyst according to an embodiment of the present invention. The above-described description of the ozone decomposition catalyst according to an embodiment of the present invention is incorporated herein by reference.

[0055] A method for manufacturing an ozone decomposition catalyst according to one embodiment of the present invention may include a step of preparing carbon nitride; and a step of mixing a precursor including the carbon nitride and an alkali metal and then heating them together.

[0056] The above carbon nitride can be purchased commercially or prepared by direct synthesis.

[0057] According to one embodiment of the present invention, the step of directly synthesizing and preparing the carbon nitride may be a step of heating a precursor containing carbon and nitrogen. Specifically, the precursor containing carbon and nitrogen is not particularly limited as long as it is known as a precursor that can be used in the synthesis of carbon nitride. For example, the precursor containing carbon and nitrogen may include one or more selected from the group consisting of urea, melamine, 2-cyanoguanidine, cyanamide, and thiourea.

[0058] According to one embodiment of the present invention, the step of heating the precursor containing carbon and nitrogen can be performed at a temperature of 400°C to 700°C, and the heating temperature can be appropriately controlled depending on the type of the precursor.

[0059] According to one embodiment of the present invention, the step of mixing a precursor including carbon nitride and an alkali metal and then heating them together can be performed at a temperature of 400°C to 700°C.

[0060] According to one embodiment of the present invention, the precursor comprising the alkali metal may be an alkali metal salt compound. For example, the precursor comprising the alkali metal may include, but is not particularly limited to, an alkali metal halide, an alkali metal nitrate, an alkali metal carbonate, an alkali metal acetate, an alkali metal butyrate, an alkali metal benzoate, an alkali metal citrate, an alkali metal alkoxide, an alkali metal nitrite, or a combination thereof.

[0061] Methods for decomposing underwater pollutants

[0062] Another embodiment of the present invention provides a method for decomposing aquatic pollutants using an ozone decomposition catalyst according to an embodiment of the present invention. The above-described description of the ozone decomposition catalyst according to an embodiment of the present invention is incorporated herein by reference.

[0063] A method for decomposing an underwater pollutant according to one embodiment of the present invention provides a method for decomposing an underwater pollutant, comprising the steps of: (a) injecting an ozone decomposition catalyst according to one embodiment of the present invention into contaminated water; (b) injecting dissolved ozone into the contaminated water; and (c) oxidizing and decomposing pollutants in the contaminated water using hydroxyl radicals generated by the ozone decomposition catalyst decomposing the dissolved ozone.

[0064] A method for decomposing underwater pollutants according to one embodiment of the present invention is an advanced oxidation process using ozone, which can non-selectively remove various trace pollutants including organic substances and can have a fast removal rate.

[0065] According to one embodiment of the present invention, the step (a) of injecting an ozone decomposition catalyst into the contaminated water and the step (b) of injecting dissolved ozone into the contaminated water may be performed first and then the step (a) may be performed, depending on the case, or the steps (a) and (b) may be performed simultaneously.

[0066] According to one embodiment of the present invention, the amount of ozone decomposition catalyst injected into the contaminated water may be 0.01 g / L to 10 g / L.

[0067] According to one embodiment of the present invention, the concentration of dissolved ozone injected into the contaminated water may be 1 to 1,000 mg / L.

[0068] The amount of ozone decomposition catalyst injected and the concentration of dissolved ozone injected can be appropriately adjusted depending on the type and amount of pollutants present in the contaminated water. Specifically, as the concentration of the ozone decomposition catalyst injected into the contaminated water increases, the rate of generation of hydroxyl radicals due to the ozone decomposition reaction may increase, but the amount of hydroxyl radicals ultimately generated may be determined by the concentration of the injected dissolved ozone.

[0069] According to one embodiment of the present invention, the step of injecting dissolved ozone into the contaminated water can be performed by a step of directly generating dissolved ozone in the contaminated water or a step of injecting an ozone solution containing dissolved ozone into the contaminated water.

[0070] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0071] Manufacturing example: Ozone decomposition catalyst

[0072] An aqueous solution of urea (CO(NH2)2, Sigma-Aldrich) was placed in a furnace equipped with heat treatment equipment and heated at a rate of 5°C / min under a nitrogen (N2) atmosphere, and heated at 550°C for 3 hours to produce carbon nitride. Then, 1.43 g of NaCl and 0.57 g of KCl were mixed with 200 mg of the carbon nitride, and the mixture was heated at a rate of 5°C / min under a nitrogen (N2) atmosphere, and heated at 550°C for 3 hours. The resulting product was washed with hot water and then dried to produce an ozone decomposition catalyst according to the present invention.

[0073] Comparative manufacturing example: carbon nitride

[0074] An aqueous solution of urea (CO(NH2)2, Sigma-Aldrich) was placed in a furnace equipped with heat treatment equipment, heated at a rate of 5°C / min under a nitrogen (N2) atmosphere, and heated at 550°C for 3 hours to produce carbon nitride.

[0075] Ozone decomposition catalyst characterization

[0076] The content of elements included in the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example was measured through X-ray photoelectron spectroscopy (XPS) analysis and is shown in Table 1.

[0077] [Table 1]

[0078]

[0079] Referring to Table 1, the ozone decomposition catalyst of the manufacturing example contained Na and K elements, and the total content of the contained alkali metal elements was 6.26 at%.

[0080] Energy dispersive X-ray spectroscopy (EDS) analysis was performed on the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example using a scanning electron microscope (SEM).

[0081] Figure 2 is a drawing showing SEM images and EDS images of the ozone decomposition catalyst of the manufacturing example. Referring to Figure 2, it was confirmed that the ozone decomposition catalyst of the manufacturing example had a porous structure with Na and K elements uniformly distributed.

[0082] Figure 3 is a diagram showing the XRD analysis results for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example. Referring to Figure 3, the ozone decomposition catalyst of the manufacturing example showed a spectrum almost identical to the XRD spectrum of the carbon nitride, confirming that the basic structure is identical to that of the carbon nitride.

[0083] Figure 4 is a drawing showing the results of FT-IR analysis for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example. Referring to Figure 4, the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example are 2000 cm -1 The peaks in the following areas were almost similar, and the ozone decomposition catalyst of the manufacturing example was at 2200 cm -1 A characteristic peak was present at 2200 cm, which was different from the carbon nitride of the comparative manufacturing example. -1 The peaks nearby indicate that the cyano group has increased in the ozone decomposition catalyst of the manufacturing example.

[0084] Fig. 5 is a diagram showing the XPS analysis results for the ozone decomposition catalyst of the manufacturing example and the carbon nitride of the comparative manufacturing example. Referring to parts (a) to (c) of Fig. 5, the C 1s and N 1s peaks have the same peak positions in the manufacturing example and the comparative manufacturing example, showing an overall similar spectrum, confirming the similarity of the carbon nitride structure. Referring to parts (d) and (e) of Fig. 5, the Na 1s and K 2p peaks were observed only in the ozone decomposition catalyst of the manufacturing example, suggesting that sodium and potassium ions are distributed within the ozone decomposition catalyst.

[0085] Example: Verification of an advanced ozone oxidation process using an ozone decomposition catalyst.

[0086] First, ozone was generated from high-purity oxygen (99.9%) using an ozone generator (OzoneTech Lab-II) in deionized water to an initial ozone concentration of 2 ppm. Then, the ozone decomposition catalyst of the manufacturing example was added to the deionized water in an amount of 0.05 g / L, and desethyl-atrazine was added at a concentration of 1 uM.

[0087] The deionized water samples were collected at 5, 10, 30, 60, and 120 minutes from the initial point (0 minutes) to measure the concentration of ozone and desethyl-atrazine.

[0088] Desethyl-atrazine has a reaction constant for ozone k = 0.2 M -1 ·s -1 , and the reaction constant for hydroxyl radicals is k = 1.2·10 9 M -1 ·s -1 As a substance, it is hardly decomposed by ozone, but is decomposed by hydroxyl radicals. Therefore, by measuring the concentration of desethyl-atrazine, the amount of hydroxyl radicals produced can be calculated, and it is suitable for evaluating the non-selective removal effect of pollutants. The deionized water samples were collected at 5, 10, 30, 60, and 120 minutes from the initial time point (0 minutes), and the concentrations of ozone and desethyl-atrazine were measured.

[0089] The concentration of ozone was measured by absorbance in the 600 nm wavelength region using a solution of indigo trisulfonate, a substance that reacts with ozone to become transparent, and a UV / Vis spectrophotometer (PerkinElmer LAMBDA 465). The concentration of desethyl-atrazine was measured using high performance liquid chromatography (High performance liquid chromatography, Thermo Scientific UltiMate 3000), using 0.1% phosphoric acid and methanol as solvents, and a C18 column (Thermo Scientific Acclaim 120).

[0090] Comparative Example 1

[0091] Except that the ozone decomposition catalyst of the manufacturing example was not added to the deionized water, deionized water samples were collected at 5, 10, 30, 60, and 120 minutes from the initial time point (0 minutes) in the same manner as in the example, and the concentration of ozone and the concentration of desethyl-atrazine were measured.

[0092] Comparative Example 2

[0093] Except that the carbon nitride of the comparative manufacturing example was added in an amount of 0.05 g / L instead of the ozone decomposition catalyst of the manufacturing example in the above deionized water, deionized water samples were collected at 5, 10, 30, 60, and 120 minutes from the initial time point (0 minutes) in the same manner as in the example, and the concentration of ozone and the concentration of desethyl-atrazine were measured.

[0094] Figure 6 shows the ozone concentration and desethyl-atrazine concentration measured for deionized water samples collected in examples and comparative examples.

[0095] Referring to part (a) of Fig. 6, it was confirmed that ozone was naturally decomposed over time in the deionized water sample collected in Comparative Example 1 without any catalyst added, but ozone remained even after 60 minutes. On the other hand, in the example in which the ozone decomposition catalyst according to the present invention was added, the ozone concentration was reduced to 0 in just 10 minutes, confirming that the ozone decomposition catalyst improved the speed of the ozone decomposition reaction and that no residual ozone remained.

[0096] Referring to part (b) of Fig. 6, it can be seen that the effect of catalyst adsorption on the decrease in the concentration of desethyl-atrazine is small, and it is assumed that most of the decrease is due to the generation of hydroxyl radicals. In the example in which the ozone decomposition catalyst according to the present invention was added, about 80% of desethyl-atrazine was removed from the initial time, and the concentration of desethyl-atrazine was measured to be about 0 from the 30-minute time point, confirming that the ozone decomposition catalyst is very effective in removing trace pollutants. On the other hand, in Comparative Example 2 in which carbon nitride of the comparative preparation example was added, a pattern in which desethyl-atrazine was reduced over time was observed, but even after 120 minutes, the removal rate of desethyl-atrazine was only 50%.

[0097] Due to the short existence time of hydroxyl radicals, direct concentration measurement is impossible. Therefore, desethyl-atrazine was used as a detector to calculate the exposure dose (concentration * time). The measured concentration of desethyl-atrazine for the examples and comparative examples and the following mathematical equations 1 and 2 were used to calculate the hydroxyl radical exposure dose for the examples and comparative examples.

[0098] The exposure to hydroxyl radicals can be expressed by the following mathematical formula 1.

[0099] [Mathematical Formula 1]

[0100]

[0101] ([P] is the concentration of desethyl-atrazine, [P]0 is the initial concentration of desethyl-atrazine, and k. OH is the reaction constant between desethyl-atrazine and hydroxyl radical.)

[0102] Since there may be an effect of desethyl-atrazine removal by adsorption of the ozone decomposition catalyst, the exposure amount of hydroxyl radicals was calculated using the following mathematical equation 2 considering adsorption.

[0103] [Equation 2]

[0104]

[0105] ([P] is the concentration of desethyl-atrazine, [P]0 is the initial concentration of desethyl-atrazine, and k. OH is the reaction constant between desethyl-atrazine and hydroxyl radical, and k ads is the adsorption constant.)

[0106] Figure 7 is a diagram showing the calculated exposure amount of hydroxyl radicals and the conversion rate of ozone into hydroxyl radicals for examples and comparative examples. Referring to Figure 7, in Comparative Example 1, the exposure amount of hydroxyl radicals was 2.6·10 -10 In contrast to M·s, the hydroxyl radical exposure in the example is 3.0·10 -9 It was confirmed that it increased by about 10 times or more as measured by M·s. In addition, in Comparative Example 1 where the ozone decomposition catalyst according to the present invention was not added, the conversion rate of ozone into hydroxyl radicals was only about 5%, which confirmed that although ozone is naturally decomposed as previously examined, the amount converted into hydroxyl radicals is minimal. On the other hand, in the Example, the conversion rate of ozone into hydroxyl radicals exceeded 40%, showing that it is an effective catalyst for the advanced oxidation process using ozone.

[0107] Experimental Example: ESR Analysis

[0108] To more directly confirm the presence of hydroxyl radicals generated by ozone decomposition, electron spin resonance (ESR) analysis was performed using DMPO (5,5-Dimethyl-1-pyrroline N-oxide).

[0109] Specifically, ozone was generated from high-purity oxygen (99.9%) using an ozone generator (OzoneTech Lab-II) in deionized water to an initial ozone concentration of 2 ppm. Then, the ozone decomposition catalyst of the manufacturing example was added to the deionized water in an amount of 0.05 g / L, and DMPO was added at a concentration of 1 uM. Immediately after the addition of DMPO, each deionized water sample was collected and ESR analysis was performed. ESR analysis was also performed on a control group under the same conditions, except that the ozone decomposition catalyst of the manufacturing example was not added.

[0110] Figure 8 is a diagram showing the ESR analysis results of an experimental example. Referring to Figure 8, when the ozone decomposition catalyst (ACN) of the manufacturing example was introduced, a signal corresponding to DMPOX (5,5-dimethylpyrrolidone-2(2)-oxyl-(1)), which is formed by the reaction of DMPO with a radical substance, was clearly confirmed, suggesting that a large amount of strong oxidizing substances such as radicals are generated in the presence of the ozone decomposition catalyst according to the present invention.

[0111] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. An ozone decomposition catalyst comprising carbon nitride and an alkali metal ion attached to the carbon nitride.

2. In claim 1, the alkali metal ion is Na + and K + An ozone decomposition catalyst comprising at least one selected from the group consisting of:

3. An ozone decomposition catalyst according to claim 1, wherein the carbon nitride comprises graphite-like carbon nitride (g-C3N4).

4. An ozone decomposition catalyst according to claim 3, wherein the graphite-like carbon nitride includes a defect.

5. In claim 4, the defective portion is a cyano group (-C≡N) O - and N - An ozone decomposition catalyst comprising at least one of the following:

6. An ozone decomposition catalyst according to claim 1, wherein the alkali metal ion attached to the carbon nitride forms a coordination bond or ionic bond with the carbon nitride.

7. In claim 1, the ozone decomposition catalyst is porous.

8. An ozone decomposition catalyst according to claim 1, wherein the content of the alkali metal element contained in the ozone decomposition catalyst is 1 to 10 at%.

9. In claim 1, in the FT-IR analysis spectrum for the ozone decomposition catalyst, 2000 to 2400 cm -1 An ozone decomposition catalyst in which at least one peak appears in the region of .

10. In claim 1, the ozone decomposition catalyst is an ozone decomposition catalyst that decomposes dissolved ozone to generate hydroxyl radicals.

11. In claim 1, the ozone decomposition catalyst is an ozone decomposition catalyst that generates hydroxyl radicals by promoting an ozone decomposition reaction expressed by the following reaction formulas (1) to (3): Reaction equation (1): O3+ e - → O3· - Reaction formula (2): O3 - + H + → HO3· Reaction equation (3): HO3· → OH·. 12.(a) A step of injecting an ozone decomposition catalyst according to any one of claims 1 to 11 into contaminated water; (b) a step of injecting dissolved ozone into the contaminated water; and (c) A method for decomposing pollutants in water, including a step in which the ozone decomposition catalyst decomposes the dissolved ozone and the hydroxyl radicals generated oxidize and decompose pollutants in the polluted water.

13. A method for decomposing pollutants in water according to claim 12, wherein the amount of ozone decomposition catalyst injected into the polluted water is 0.01 g / L to 10 g / L.

14. A method for decomposing pollutants in water according to claim 12, wherein the step of injecting dissolved ozone into the polluted water is performed by a step of directly generating dissolved ozone in the polluted water or a step of injecting an ozone solution containing dissolved ozone into the polluted water.

15. A method for decomposing pollutants in water according to claim 12, wherein the concentration of dissolved ozone injected into the polluted water is 1 to 1,000 mg / L.

16. A method for producing an ozone decomposition catalyst according to any one of claims 1 to 11, Step of preparing carbon nitride; and A method for producing an ozone decomposition catalyst, comprising the step of mixing a precursor containing the above carbon nitride and an alkali metal and then heating them together.

17. A method for producing an ozone decomposition catalyst according to claim 16, wherein the step of preparing the carbon nitride is a step of heating a precursor containing carbon and nitrogen.

18. A method for producing an ozone decomposition catalyst according to claim 17, wherein the precursor containing carbon and nitrogen comprises at least one selected from the group consisting of urea, melamine, 2-cyanoguanidine, cyanamide, and thiourea.

19. A method for producing an ozone decomposition catalyst according to claim 17, wherein the step of heating the precursor containing carbon and nitrogen is performed at a temperature of 400°C to 700°C.

20. A method for producing an ozone decomposition catalyst according to claim 16, wherein the step of heating the precursor including carbon nitride and alkali metal together is performed at a temperature of 400°C to 700°C.

Images